In the conventional manner for supplying heat to floors, hot pads, or the like, electricity is generally utilized, and these conventional blankets, floors, or hot pads to be electrically heated are effective as one of various local heating or keeping warm ways.
However, since the electrical heating device uses an electric heating wire as its heat source, electromagnetic waves harmful to the human body are generated. Researches teach that the minimum intensity of electromagnetic waves harmful to the human body is between 2 mG and 4 mG. Comparing this, the intensity of electromagnetic waves generated from the electric heating device ranges from 50 mG to a value exceeding 1,000 mG.
As described above, since the conventional electric heating device has a shortcoming in that it is harmful to human health, use by the pregnant, the old and weak as well as ordinary people is being limited.